»sidecar_task Stanza

The sidecar_task stanza allows configuring various options for the proxy sidecar managed by Nomad for Consul Connect integration such as resource requirements, kill timeouts and more as defined below. It is valid only within the context of a connect stanza.

job "countdash" {
  datacenters = ["dc1"]

  group "api" {
    network {
      mode = "bridge"
    }

    service {
      name = "count-api"
      port = "9001"

      connect {
        sidecar_service = {}

        sidecar_task {
          resources {
            cpu    = 500
            memory = 1024
          }
        }
      }
    }

    task "web" {
      driver = "docker"

      config {
        image = "hashicorpnomad/counter-api:v2"
      }
    }
  }
}

»Default Envoy proxy sidecar

Nomad automatically includes a default Envoy proxy sidecar task whenever a group service has a sidecar_service stanza.

The default sidecar task is equivalent to:

   sidecar_task {
     name   = "connect-proxy-<service>"

     lifecycle {
       hook = "prestart"
       sidecar = true
     }

     driver = "docker"
     config {
       image = "${meta.connect.sidecar_image}"
       args  = [
         "-c",
         "${NOMAD_SECRETS_DIR}/envoy_bootstrap.json",
         "-l",
         "${meta.connect.log_level}"
       ]
     }

     logs {
       max_files     = 2
       max_file_size = 2 # MB
     }

     resources {
       cpu    = 250 # MHz
       memory = 128 # MB
     }

     shutdown_delay = "5s"
   }

The meta.connect.sidecar_image and meta.connect.log_level are client configurable variables with the following defaults:

• sidecar_image - (string: "envoyproxy/envoy:v${NOMAD_envoy_version}") - The official upstream Envoy Docker image, where ${NOMAD_envoy_version} is resolved automatically by a query to Consul.
• log_level - (string: "info") - Envoy sidecar log level. "debug" is useful for debugging Connect related issues.

meta.connect.sidecar_image can be configured at the job, group, or task level. Custom images can make use of Consul's preferred Envoy version by making use of Nomad's version interpolation, e.g.

meta.connect.sidecar_image = custom/envoy-${NOMAD_envoy_version}:latest

»sidecar_task Parameters

• name (string: "connect-proxy-<service>") - Name of the task. Defaults to including the name of the service it is a proxy for.

• driver (string: "docker") - Driver used for the sidecar task.

• user (string: nil) - Determines which user is used to run the task, defaults to the same user the Nomad client is being run as.

• config (map: nil) - Configuration provided to the driver for initialization.

• env (map: nil) - Map of environment variables used by the driver.

• resources (Resources) - Resources needed by the sidecar task.

• meta (map: nil) - Arbitrary metadata associated with this task that's opaque to Nomad.

• logs (Logs: nil) - Specifies logging configuration for the stdout and stderr of the task.

• kill_timeout (string: "5s") - Time between signalling a task that will be killed and killing it.

• shutdown_delay (string: "5s") - Delay between deregistering the task from Consul and sending it a signal to shutdown.

• kill_signal (string:SIGINT) - Kill signal to use for the task, defaults to SIGINT.

»sidecar_task Examples

The following example configures resources for the sidecar task and other configuration.

   sidecar_task {
     resources {
       cpu = 500
       memory = 1024
     }

     env {
       FOO = "abc"
     }

     shutdown_delay = "5s"
   }